1. Field of the Invention
This invention relates in general to certain new and useful improvements in a container system for the storage and transport of fresh leafy vegetables and more particularly, to a storage and transport system and associated method which permits storage of bulk quantities of such vegetable produce in large stackable paperboard containers and which also reduces the problems of deterioration and spoilage.
2. Brief Description of the Prior Art
Vegetables, such as lettuce, and other produce are frequently shipped to a processing facility from a farm site to a processing facility and often from a processing facility to a site of use in paperboard containers. However, lettuce heads and like produce often contain substantial amounts of entrained water and which leaves the vegetable heads in the form of sap or through evaporation through the leaves. The moisture from this produce penetrates the side walls of the paperboard container, thereby weakening the container often causing a premature rupture or tear of the container during transport. In such a case, if the container ruptures during transit, the entire container and the produce contained therein may be discarded, thereby resulting in loss.
In addition to the above, the moisture from the fresh produce, and particularly fresh leafy produce such as lettuce heads and the like, often penetrates the paperboard containers and wets the containers which further harbors and promotes bacterial growth. The only known technique for reducing the bacterial growth and maintaining the vegetable product in a fresh state is to store and ship the fresh vegetable products in a reduced temperature environment. While this may inhibit bacterial growth, it does not eliminate such growth.
Due to the foregoing problems, in order to ship fresh leafy vegetable products, the containers have had to be of a fairly thick and substantial construction. While this does reduce some of the rapid deterioration from water released from the produce, it does not overcome the bacterial growth problem. Moreover, the very fact that the containers are of a more durable construction substantially increases the weight and hence, the overall transport cost of the containers. Due to the fact that many of these vegetable products must be transported for a period of several days, e.g., six or more days, the containers must be of sufficient durability to maintain their structural integrity for this transit period.
In the prior art, fresh leafy vegetables, such as lettuce heads and the like, are generally transported in rectangularly shaped paperboard containers. Moreover, these paperboard containers are usually of a disposable construction. Due to the fact that these containers are usually disposed of at a site of use, the overall cost of storage and transport is increased and moreover, there is the resultant problem of disposing of the used paperboard containers, not to mention the environmental impact resulting therefrom. In addition to the foregoing, these containers are often punctured by nails in pallets during storage and other transit. This misuse and rough handling further militates against the reuse of the containers.
It is well known that heads of lettuce deteriorate rapidly in the presence of oxygen. It is therefore desirable to store and transport the lettuce in a relatively oxygen-free environment. There have been attempts to package heads of lettuce in relatively small quantities (e.g. six to eight heads of lettuce) in a plastic bag which is then sealed with a relatively inert atmosphere such as carbon monoxide. However, these packaging techniques are used for specific purposes where only a very small quantity of the vegetable product is transported.
In our co-pending U.S. patent application Ser. No. 915,093, filed Jul. 16, 1992, there is provided both a container system and a method for transporting of fresh vegetable products, such as leafy head lettuce and the like, in a liner located in a reusable paperboard container. Also, in this aforesaid patent application, there is also provided an embodiment wherein a pair of plastic liners are used with lettuce stored in an inner plastic liner which is then sealed and charged with an oxygen rare atmosphere and where the space between the inner and outer liner is also charged with an oxygen rare atmosphere. This type of packaging system and method has been effective for reducing the deterioration and discoloration of lettuce products at a destination.
This packaging system and method in the aforesaid U.S. patent application also reduces the attendant labor costs for removing the discolored or deteriorated outer leaves of lettuce heads. The process and container system of the aforesaid patent application is effective so that lettuce heads and like food products can be cored, that is, have the center cores removed, at a farm site where lower labor cost is generally available. In this way, the farm-fresh produce can reach a site of destination where it is not necessary to core the lettuce with substantially higher labor costs.
One of the problems attendant to the shipping and transport of lettuce is the fact that it is necessary to transport the lettuce in large containers and moreover, to provide containers of durability so that they are stackable on one another. In many cases, several hundred heads of lettuce must be stored in a single container and this container itself can weigh up to eight or nine hundred pounds. When one or more like containers are stored on a container of this construction, it is apparent that there is a substantial and compressive load on the lowermost container. Thus, this lowermost container must be of a construction to withstand the weight of the containers stacked thereon. However, resort to a thicker sidewall construction of the container only increases the overall thickness of the container and hence, the overall weight which is transported.
In addition to the above, it is necessary for any container to generally have a size and shape which will conform to a pallet upon which the container itself may be stored. In most cases, the pallets are of a wood construction and are usually rectangular, if not square, in shape. As a result, any construction must conform to and generally achieve a rough marginal registration with the upper surface of a pallet.
Octagonally-shaped containers having four elongate side walls connected by four relatively short length sidewalls, in an irregular octagonal arrangement, have been used for transporting of watermelons. Thus, and to that extent, octagonally shaped containers somewhat similar to those of the present invention have been used in the past. However, the octagonally shaped containers used for watermelons were severely limited in size and particularly in height. In fact, it has been found that these containers could have an overall height of no more than 36 inches. In many cases, the container had to be constructed with a height of less than 36 inches in order to withstand the weight of the watermelons.
In addition to the foregoing, the prior art containers used for transporting of watermelons had a relatively thick sidewall construction. As a result, the overall cost and weight of the container used to hold the watermelons was substantially increased. However, due to the fact that the watermelons themselves exhibited such substantial weight, the increase in weight from the extra thick wall of the container was not that significant. Contrariwise, the additional weight provided by an additional thickness of a sidewall construction would add materially to the overall weight of lettuce when being transported.